高变分段低贫化放矿及其参数优化试验研究

放矿工作是无底柱分段崩落法的核心工作，结构参数的选取则是放矿工作所要解决的重要内容，其直接影响着采场的出矿效率及各项回贫经济指标。采场主要结构参数是分段高度、进路间距和崩矿步距，根据放矿学理论，这3个参数的不同组合将直接影响最终的回贫指标。大红山铁矿一期采用的是20 m×20 m的大结构参数组合，即分段与进路间距都为20 m，二期规划拟在400 m水平以下采用30 m×20 m的结构参数，即将分段高度提高到30 m，属于高变分段放矿形式。针对大红山铁矿二期高变分段的放矿形式，利用实验室相似材料制作放矿模型，进行低贫化放矿研究，得到了高变分段下放出体发育形态，高变分段下最优崩矿步距及进路口规格，试验结果证明采用低贫化放矿明显提高了资源回收率，有效降低了矿石的损失贫化。

Experimental Study on Low Dilution Drawing of High and Variable Sublevel and its Parameter Optimization

Ore drawing is the core work of the pillarless sublevel caving method，and the selection of the structural parameters in stope is an important work of ore drawing，which directly impacts on the mining efficiency and mining economic indicators (including recovery and dilution depleted).The main structural parameters of the stope are sublevel height，access space and caving step.According to the theory of ore drawing，different combinations of these three parameters will affect the final index.Large structural parameters combination of 20×20m was used in phaseⅠof Dahongshan iron mine，and sublevel height and access space were both 20m.phase II planned to adopt 30×20m structural parameters combination，that is，the sublevel height is raised to 30m，which belongs to high and variable sublevel ore drawing.In connection with the high and variable sublevel ore drawing in Phase II Project of Dahongshan Iron mine，similar materials in laboratory were used to produce ore drawing model and conduct low dilution ore drawing research，achieving the developmental morphology of drawn-out ore-body，optimal caving space and intersection hole under high and variable sublevel condition.The test results prove that the low dilution ore drawing significantly improved resource recovery，and effectively reduced ore loss and dilution.